Content last revised on November 12, 2025
Mitsubishi QM75DY-H | Robust 600V, 75A Dual Darlington Power Module for Industrial Drives
The Mitsubishi QM75DY-H stands as a testament to proven engineering in the power electronics landscape. This dual Darlington transistor module is engineered for exceptional reliability and durability in high-current, low-to-medium frequency applications. While newer technologies have emerged, the QM75DY-H remains a strategic choice for designers prioritizing ruggedness, simplified drive requirements, and long-term field reliability in demanding industrial environments.
- Proven Reliability: Built on established BJT technology, this module offers a predictable and robust performance profile, ideal for legacy system maintenance or new designs where durability is paramount.
- High Current Gain (hFE): The Darlington configuration significantly simplifies the base drive circuitry, reducing the required drive current and potentially lowering overall system cost and complexity.
- Dual Configuration: Integrates two Darlington transistors in a single, thermally efficient package, making it perfect for half-bridge topologies found in motor inverters and power converters.
- Industry-Standard Package: Housed in a standard package with an electrically isolated baseplate, ensuring straightforward mounting and excellent thermal dissipation to a heatsink.
Key Parameter Overview
For engineers requiring quick-access data, the following table summarizes the critical electrical and thermal characteristics of the Mitsubishi QM75DY-H. For a complete dataset, you can download the official datasheet here.
| Parameter | Symbol | Value |
|---|---|---|
| Collector-Emitter Voltage | VCEO | 600 V |
| Collector Current (DC) | IC | 75 A |
| Collector-Emitter Saturation Voltage | VCE(sat) | 2.5 V (Typ) @ IC = 75A |
| DC Current Gain | hFE | 75 (Min) @ IC = 75A, VCE = 2V |
| Total Power Dissipation | PC | 480 W |
| Operating Junction Temperature | Tj | -40 to +150 °C |
Application Scenarios & Value Proposition
The QM75DY-H excels where raw power handling and resilience are more critical than ultimate switching speed. Its value is most evident in the following applications:
- AC Motor Drives: In Variable Frequency Drives (VFDs) operating at lower PWM frequencies (typically below 5 kHz), the low conduction losses and high surge current capability of the QM75DY-H ensure reliable motor control for conveyors, pumps, and fans.
- Welding Power Supplies: The module's inherent toughness allows it to withstand the significant electrical stresses and thermal cycling common in arc welding and resistance welding equipment.
- Uninterruptible Power Supplies (UPS): Its track record of reliability makes it a trusted component for the inverter stage of industrial UPS systems, guaranteeing dependable power conversion when it matters most.
- General Purpose Inverters: For cost-sensitive power conversion tasks, this module provides a robust and economical solution without the complexities of managing the faster switching edges of modern IGBTs.
Technical Deep Dive: The Engineering Behind the Reliability
Understanding the design philosophy of the Mitsubishi QM75DY-H reveals its enduring relevance. Two key aspects define its performance:
1. The Darlington Pair Advantage: This module utilizes a Darlington configuration, which connects two Bipolar Junction Transistors (BJTs) in cascade. The primary benefit is an exceptionally high DC current gain (hFE). This means a small base current can control a very large collector current, significantly simplifying the required drive circuitry. For many designs, this translates into a more straightforward and robust gate drive design compared to driving a single, high-power BJT directly.
2. Thermally-Engineered Packaging: The module features a copper baseplate that is electrically isolated from the transistor terminals. This design accomplishes two critical engineering goals simultaneously. First, it provides a low thermal resistance path to an external heatsink, which is essential for managing heat and preventing overtemperature failures. Second, the isolation simplifies mechanical assembly, as the module can be mounted directly to a grounded chassis or heatsink without requiring extra insulating layers, reducing assembly time and improving thermal performance.
Frequently Asked Questions (FAQ)
Is the QM75DY-H an IGBT module?
No, the QM75DY-H is a Darlington Transistor Module, which is based on BJT technology. While used in similar power switching applications, their control methods differ. Darlingtons are current-controlled devices, while modern IGBTs are voltage-controlled. For a detailed comparison of these technologies, our guide on IGBT vs. MOSFET vs. BJT selection provides an in-depth analysis.
Why choose a Darlington module in an era of advanced IGBTs?
The primary reasons are proven robustness, predictable performance, and cost-effectiveness for specific applications. For systems operating at lower switching frequencies where conduction losses are the dominant factor and the design has a long history of field deployment, the QM75DY-H offers a reliable, low-risk solution that avoids the cost and validation effort of a complete redesign with newer components.
For help determining if the Mitsubishi QM75DY-H is the optimal choice for your specific application, please contact our technical team for an expert consultation.
